Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte Carlo (RHMC) Algorithm

TL;DR

This paper demonstrates that using the exact Rational Hybrid Monte Carlo (RHMC) algorithm in lattice QCD calculations with staggered fermions significantly reduces computational costs and eliminates step-size errors compared to the traditional inexact R algorithm.

Contribution

The paper introduces the application of the exact RHMC algorithm to improved staggered fermion formulations in lattice QCD, showing substantial efficiency gains and error elimination.

Findings

RHMC reduces computational cost by a factor of about seven.

RHMC has no step-size errors unlike the R algorithm.

Applicable to current state-of-the-art lattice QCD computations.

Abstract

Improved staggered fermion formulations are a popular choice for lattice QCD calculations. Historically, the algorithm used for such calculations has been the inexact R algorithm, which has systematic errors that only vanish as the square of the integration step-size. We describe how the exact Rational Hybrid Monte Carlo (RHMC) algorithm may be used in this context, and show that for parameters corresponding to current state-of-the-art computations it leads to a factor of approximately seven decrease in cost as well as having no step-size errors.